1 Field of the Invention
The invention relates to a power supply arrangement for applying direct current to subscriber circuits in a telephone system, comprising:
a controllable pulse generating arrangement which for its supply is connectable to a central supply source,
a control arrangement connected to the pulse generating arrangement for having the pulse generating arrangement supply current pulses under the control of control signals produced by the control arrangement and
smoothing circuits provided in a one-to-one relationship with the subscriber circuits and connected to the pulse generating arrangement for converting the current pulses produced by the pulse generating arrangement into smoothed direct current.
2. Description of the Related Art
Such a power supply arrangement is disclosed in U.S. Pat. No. 3,965,447.
The power supply arrangement described in this United States Patent comprises a pulse arrangement in the form of a pulse source which applies current pulses to a plurality of smoothing circuits which each apply direct current to a subscriber line. As all the smoothing circuits are connected in parallel with each other to the pulse source significant current changes are produced in the d.c. voltage source from which the pulse source is supplied.
In a telephone system in which a plurality of smoothing circuits is provided with current pulses by one central pulse generating arrangement, the significant current changes in the central supply source produce a voltage ripple across the internal resistance of this supply source. This voltage ripple has a disturbing effect on the telephone system.